1) First, take your white card and mark two pieces. The largest piece is 4.5"x8" (11cmx21cm) which is going to be your base card, and the smaller piece is 3.75"x6.5" (8cmx17cm) which will be your insert.
Here is how we fit them onto the sheet of card:

2) Cut out the pieces and score your larger piece at 4cm and your smaller piece at 3cm. Here are the two pieces you should have:

3) Now, take your larger piece and cover the inside of it with your largest piece of backing paper. Like so:

4) Now, cover the remaining white flap on the front of your card:

5) These two pieces are the only bits of your base card that are seen so you do not need to cover any more of the base card. When lay flat, this is what pieces of card I have covered:

6) Now, take your smaller piece of card and cover the shorter side, when folded, in plain paper:

7) Now, we are going to layer up our main image. I find it easier to trim around the tree and layer up rather than layering from the card and finding that my main image is too large to fit! First, I'm going to layer my tree onto patterned paper:

Then add a small rim of white behind it:

8) Now, I'm going to add this to the red part of my smaller piece of card:

9) Now, take your paper lace and lay this down the edge of your red card front like so: